Re: the subject
Wait and buy it if you want the game particularly on Switch. If you want it now more than you particularly want it on Switch, buy it at launch on another platform.
I don't suggest politicizing your purchases over things like "which platform do you support." Even if your purchase was particularly weighty (it isn't, taken alone), I don't think there is any way to send your intended message here: the only messages you can send is "I want this game, even late" or "I don't want this game."
Re: Switch port-begging
There is a mismatch between a) Switch's success, b) the resonance of the hybrid proposition, and c) the current demographics of the Switch and d) the support Switch is getting. There is also a mismatch between e) Nintendo's positioning of the Switch wrt current development streams (particularly in Japan), f) the sales success of Switch, and, again, c) the current demographics of the Switch and, again, d) the support Switch is getting. That is, considering both of these mismatches, Switch g) has owners that want more games on Switch that don't traditionally come to Nintendo platforms and h) should probably be getting more such games than it currently is.
Yes: Nintendo has a history of marching to the beat of its own drum. It has a history of weak third party relations. It has a history of recent failure in home consoles. Handhelds seemed on a strictly downward trajectory and most doomed by mobile.
Put up against competitors that produce machines third parties expect and understand and who have a proven market, which beat off fears of extinction handily at the start of the generation, and it is obvious, if unfortunate, why Nintendo is left out of so many equations or an after-thought.
Nintendo has done a lot with the Switch to simultaneously do their own thing and to make themselves attractive to people doing other things. I think they have a winning formula and that should attract growing support but there is going to be sluggishness and resistance. There is going to be failure of things, which really ought to be on Switch, being on Switch.
I just hope the final picture is incredibly vibrant. Switch could be so much.